A kind of method of topology optimization design for the supporting structure was presented, which aimed at decreasing the acceleration response RMS value of the space cameras. Firstly, after analyzing the common various forms of the space camera supporting structure, a supporting pattern with the secondary mirror and the folding mirror fixed separately was determined according to the characteristics of this optical system. Secondly, a trussed supporting structure met the requirements on the acceleration response was designed, which directed by objective function of acceleration response RMS and in the meanwhile restricted by the volume fraction, the displacements of the secondary mirror with the influence of axial gravity and the first-order frequency of the supporting structure. Finally, the finite element analysis and vibration experiments show that the supporting structure could satisfy the requirements on the whole mechanics performance index of this camera. The fundamental frequency reaches 291.4 Hz, and the acceleration response RMS value is 5.08 g with 2 g RMS random load under the condition that the mass of this trussed supporting structure is not more than 4 kg. The design scheme of this trussed supporting structure could provide some reference to the other light-small space camera with the same type.